Process and appratus for the production of hydroelectric pulsed liquids jets

ABSTRACT

Process and apparatus for producing high energy pulsed liquid jets by the discharge of electrical energy through a relatively incompressible liquid in an essentially closed chamber having a shaped outlet nozzle.

United States Patent Naydan et al.

151 3,700,169 [451 Oct.24, 1972 PROCESS AND APPRATUS FOR THE [56]References Cited PRODUCTION OF HYDROELECTRIC UNITED STATES PATENTSPULSED LIQUIDS JETS 2,881,092 4/1959 Sedlacsrk, Jr. ..239/102 X2,512,743 6/1950 Hansel] ..239/10l X Inventors: Theodore T. Naydan;Walter W. 3,114,654 12/1963 Nishiyama et al. ....239/l02 X Aker, h fSchenectady, NY. 3,281,860 10/1966 Adams et a1. ..239/102 X r 3,400,8929/1968 Ensminger ..239/102 3,373,752 3/1968 lnoue ..134/1 Assignee:Environment/One Corporation,

Schenectody, N.Y. Primary ExaminerLloyd L. King AttomeyCharles W.l-lelzer and ALbert C. Hodgson F116C11 Oct. 20, 1970 [57] ABSTRACT PPN05 82,319 Process and apparatus for producing high energy pulsed liquidjets by the discharge of electrical energy hrough a relativelyincompressible liquid in an essenu.s. c1 .139/4, 239 102 lnt. Cl. ..B05b17/04 closed chamber havmg a Shaped outlet nozzlef Field of Search..239/1 5, 101, 4, 102 16 Claims, 7 Drawing Figures PATENTEDucI 24 m2SHEET 2 0F 3 NVENTORS ATTORNEY SHEET 3 [1F 3 PATENTEU 0m 24 I972INVENTO'S THEODORE T. NAYDAN WALTER w. AKER BY wn/; Meg

ATTORNEY PROCESS AND APPRATUS FOR THE PRODUCTION OF HYDROELECTRIC PULSEDLIQUIDS JETS BACKGROUND OF THE INVENTION 1. Scope of the Invention Thisinvention relates generally to a method and apparatus for generatingpulsed water jets and, more particularly to a method and apparatus forthe generation of high repetition rate pulsed water jets by thedischarge of electrical energy.

2. The Prior Art In the field of subterranean mining there hasheretofore been employed conventionally a moil which is a metal cuttingtool used for cutting away hard rock material in the mining area. Thesecutting tools are made of hard metal, but they erode during the cuttingprocess, thereby limiting the amount of material removed and curtailingthe speed of mining.

In recent years, due to the increased need for rapid undergroundexcavation for the removal of valuable material and for the developmentof subterranean channels for rapid transit and for materials handling,hydraulic mining techniques have been developed with the goal of longlife, low cost and easily maintainable equipment. Such hydraulictechniques have included the use of hydraulic amplifiers and jack hammertype oscillators to generate the requisite peak pressures foraccelerating water missiles to high velocities. Such equipment is bulkyand has an inherent high noise factor producing unsuitable workingconditions.

SUMMARY OF THE INVENTION In accordance with the present invention, ithas been discovered that the discharge of stored electrical energy froma capacitor or other suitable source into a closed container of asuitable fluid such as water by means of proper coupling electrodes willgenerate high temperature channel between the electrodes. This dischargewill produce three effects: (1) a high pressure sonic front travellingoutward from the discharge channel: (2) a high temperature expandinggaseous bubble containing superheated steam and a substantial amount ofionized species and neutral moleculesz'and (3) a continuum of highintensity light coincident with the time of discharge. A study of atypical system according to the present invention has revealed that theconversion from electrical energy to heat, sound and light is highlyefficient, utilizing about fifty percent (50 percent) of the totaldischarge energy, the remainder being lost in the external circuitry.

Delivery of the high voltage electric energy to the spark gap is at afaster rate than the ability of the fluid medium to absorb the heatgenerated thereby. Consequently, the fluid medium in the gap isvaporized, undergoing at least partial ionization. Upon discharge of theelectrical energy, a gaseous bubble is formed in the channel between theelectrodes. Expansion of the bubble takes place during the relativelyshort time period of energy release, producing a shock wave in therelatively incompressible liquid. Since the reaction vessel iseffectively a closed container except for the jet nozzle at the time ofdischarge, this shock wave meets mechanical resistance at all directionsexcept through the nozzle opening. Thus a pulsed liquid jet is forcedthrough the jet nozzle opening. This pulsed liquid jet is in the form ofa liquid slug and is under extremely high pressure. When directed ontoor against a desired surface, the Kinetic energy of the liquid slug iscapable of useful work such as shaping, fracture and the like.

Several methods can be employed to supply the liquid to the reactionchamber. A suitable method would include a continuous liquid feedthrough the jet opening, producing a continuous stream out of the nozzlewhen unpulsed and an automatically pulsed stream when the electricalcircuitry is actuated.

The apparatus of the present invention can also function in an opensystem whereby the electrode gap area is replenished by the action ofthe surrounding fluid medium. A mechanical shutter can be employed forthe nozzle opening in such a manner that uncovering the nozzle openingautomatically triggers the electrical discharge.

A continuous and predictable electrical discharge is important to thesuccessful application of thepresent application. This canbe provided bysuitable electrode design. The use of ungrounded sleeves for theelectrodes will produce a capacitive voltage divider across theelectrode gap with the shell of the apparatus connected to the centraljunction point of the capacitors. Thus upon initiation of the dischargecycle, the high voltage starting gradients from the side wall of theapparatus to the sleeves will be half the gradient to the electrodes,providing a controlled and predictable streamer discharge.

A freely accelerating piston can also be employed to supply the liquidto the reaction chamber. In such an application, the piston will deliverthe liquid at a high pressure, which pressure will be even furtherincreased by the discharge of electric energy. Thus the magnitude of theforce possessed by the resultant liquid jet is markedly increased overthat supplied by the piston.

The electrohydraulic liquid jet units of the present invention can alsobe used in combination with known mining techniques and equipment. Thedevice of the present invention can be used in combination with tungstencarbide or very hard steel bits in the cutting of hard rock to ease thejob of cutting and to increase the life of the bits. In such anapplication, a multiplicity of electrohydraulic jet units can bearranged vertically for travel along a mine wall preceding the travel ofthe cutter bits along the mine face. By this arrangement, the waterslugs will lacerate and weaken the wall by forming horizontal slabs.Subsequent cutting by the bits is much easier and the resultantreduction in bit wear and erosion increases bit life.

The electrohydraulic jet units can also be employed to drive awater-soluble resin into the bedding planes of a mine wall when suchresin is added to the liquid supplied to the jet. These water-solubleresins, such as Polyox, will reduce the coefficient of friction betweenadjacent surfaces by as much as 68 percent when dispersed in water to aconcentration of 30 ppm. The use of such a mixture will cause thebedding planes to part more easily and will also serve as a lubricantfor cutting bits which follow the electrohydraulic jets.

The application of heat to weaken rock and cause it to spall and crackin depth is well known. If the percentage of water in the rock isproper, the spalling, weakening and cracking of the rock is greatlyenhanced. Where strata are encountered which are deficient in watercontent, the electrohydraulic jets of the present invention can be usedto saturate the bedding planes prior to the application of heat. In suchapplication, the heat and high pressure jets can be appliedsimultaneously or alternately, the heat causing expansion stresses inthe rock and the slugs of water tending to cool and crack the rock.Subsequent cutting by mechanical bits can be employed where desired.

In some applications of mining techniques, a rock slab will break loosebut will hang up on the mine face due to an effect known as keystoning.Such problems are eliminatedby the present invention since the liquidDESCRIPTION OF THE DRAWINGS The features of this invention together withfurther objects and advantages thereof, may best be understood byreference to the accompanying drawings wherein? FIG. 1 is across-sectional view of one embodiment of an electrohydraulic jetapparatus accordingto the present invention;

FIG. 2 is a cross-sectional view of a second embodiment of anelectrohydraulic jet apparatus according to the present invention;

FIG. 3 is a schematic illustration of a plow assembly employing aplurality of electrohydraulic jet apparatus according to the presentinvention in combination with a plurality of metal moils; and

FIG. 4 is a schematic illustration of a plow assembly employing aplurality of electrohydraulic jet apparatus according to the presentinvention, in combination with a plurality of heating units and aplurality of metal moils.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The process and apparatus canbest be described with reference to the drawings. For purposes ofillustration, a single electrohydraulic jet apparatus will be described.It will be readily understood that such jets may be employed singly orin any desired number arranged in any configuration designed to achievea desired result.

Specifically, the apparatus includes a container which defines areaction chamber 11 having a nozzle 12. Liquid is supplied to thecontainer through a pressurized line 13 and enters the reaction chamber11. The liquid preferably is water but may comprise any suitablenon-explosive fluid having characteristics tailored for a particularoperation such as improved lubricating qualities for enhancing theperformance of mechanical moils. The fluid enters reaction chamber 11through a port 14. This port may be provided with valve means 15operable to seal the reaction chamber 11 during production of the jet.Coupling electrodes 16, 17 extend into'the reaction chamber 11. Theseelectrodes 16, 17 are insulated from the container 10 by insulatingmeans 18, 19. Metallic sleeves 20, 21 are provided for each electrode16, 17. The sleeves 20, 21 are mechanically and electrically connectedto container 10 and are not grounded. The electrodes 16, 17 areconnected through switch means 22 to a source of electrical energy whichmay be a capacitor bank 23 which is in turn connected across a highvoltage power source (not shown). Any suitable source of electricalenergy can be employed in this embodiment. In addition to the preferredcapacitor bank, induction coils, transformers and the like may be used.For illustration purposes the source of electrical energy has been shownas a capacitance 23. Because the electrode sleeves 20, 21 and container10 are not grounded,'they serve as a capacitive voltage divider acrossthe gap between the electrodes 16, 17 when the switch means 22 isactuated. One plate of the capacitance 23 is connected to ground at tothe electrode 17. Upon actuation of the switch means 22 which can be agas discharge tube, a triggered gap or the like, the high voltagestarting gradients from the side walls of the container 10 to electrodes16, 17 are always half the gradient across the electrodes. This ensuresa controlled and predictable streamer discharge across the electrodegap. The insulating means 18, 19 also serve to prevent unpredictablefiring across the gap after erosion of the electrodes by ensuring thatthe gradient between the electrodes is greater than the electrode towall gradient.

Prior to actuation of the device, the reaction chamber is substantiallycompletely filled with liquid supplied through the port 14. When theelectrical energy stored in the capacitance 23 is discharged across theelectrodes 16, 17 by actuation of the switch means 22,

a high temperature channel is generated between the electrodes 16, 17with the following effects: (1) a high pressure sonic front travellingoutward from the discharge channel: (2) a high temperature expandinggaseous bubble containing superheated steam and a substantial amount, ofionized species and neutral molecules: and (3) a continuum of highintensity light coincident with the time of discharge. Studies haveshown that the conversion from electrical energy to heat, sound andlight is highly eff cient, utilizing about fifty percent (50'percent) ofthe total discharge energy, the remainder being lost in the externalcircuitry. Some of the sound produced within the container 10 and alllight produced therein is absorbed in the liquid and reconverted intousable heat. The time of discharge of the capacitor circuit is of theorder of 50 microseconds. During this interval about 27,000 horsepowerof total energy per kilojoule of energy supplied-is released into theliquid in the reaction chamber 11 while the liquid is in a substantiallystatic condition. The extremely high temperatures (20,000 30,000 K) andpressures (100,000-200,000psi) developed in the channel between theelectrodes 16, 17 cause the gaseous bubble formed therein to expand at avery rapid rate. Check means such as ball valve 15 serve to close theliquid entry port 14 and thus the liquid confined within the reactionchamber 11 meets mechanical resistance in all directions except throughthe nozzle opening 12. This nozzle opening 12 is preferably locatedon-center with the position of the spark discharge between theelectrodes 16, 17.

If desired, shutter means 24 may be employed to close the nozzle opening12 between pulses. The shutter means 24 can be actuated electrically ormechanically and may be connected through a circuit 25 to a sensor 26which is in turn connected to the switch means 22. The sensor 26 acts tosynchronize the opening of the shutter 24 with the discharge of thecapacitance 23 to effect proper operation. Valve means or the like canbe employed in place of. the shutter 24. For example, anelectromagnetically actuated solenoid valve could be used to alternatelyopen and close the nozzle opening 12.

Referring to FIG. 2, an embodiment is shown in which a freelyaccelerating piston 30 is employed to compress the liquid in thereaction chamber 11 prior to discharge of the capacitor 23 between theelectrodes l6, 17. The liquid is supplied to the reaction chamber 11through suitable means such as port 31. In this embodiment, the piston30 is driven at a high rate of speed through a cylinder 32 by externalpower means (not shown). The piston 30 picks up the liquid supplied bythe port 31 and accelerates this liquid during delivery into reactionchamber 11. The liquid thus enters the reaction chamber 11 at a highrate of speed and with considerable force. It fills the reaction chamber11 and at the instant that the chamber is filled with the substantiallyincompressible fluid, i.e. at top-dead-center of the piston, switchmeans 22 cause discharge of the capacitance 23 between the electrodes16, 17. The rapidly expanding gaseous bubble created by the electricdischarge adds even greater force to that already transferred to theliquid by the piston 30 which is instantaneously locked in itsforwardmost position so as to confine the space of reaction chamber 1 1and is then retracted by an appropriate connecting rod and acceleratingmechanism. Since at the instant of electric discharge the reactionchamber 11 is essentially a closed vessel having only a nozzle opening,all of the force will be directed in driving a slug of water through thenozzle opening.

In FIG. 3 there are shown a multiplicity of electrohydraulic jet units10 arranged serially one above the other on a common plow or stand 40. Asuitable number of metal cutting bits or moils 41 are also arranged onthe stand in cooperative relationship with the jet units 10. The standis mounted on a suitable means such as rails 42 for travel laterallyacross a mine wall or the like so that the surface thereof is acted onby the electrohydraulic jet units 10 and then the metal cutting bits 41.Suitable transport means 43, such as wheels or tracks or the like,suitably powered may be employed to advance the stand 40 in thedirection of the mine wall after each pass across the mine face so thatthe units are repositioned to remove additional material. The rock isfractured by the action of the electrohydraulic jet units 10 and thencomplete removal is effected by the action of the cutting bits 41.

Referring to FIG. 4 there are shown a multiplicity of electrohydraulicjet units 10 arranged serially one above the other on a common plow orstand 40. A bank 50 of infrared heating units 51 each having a filament52 surrounded by a reflector 53 is mounted adjacent the electrohydraulicjet units 10. In the operation of this embodiment, the stand 40 isadvanced toward the mine face by the motive means 43. The

stand 40 travels across the mine face on rails 42. The rock of the mineface is first heated by the heating units 51 and then the action of theelectrohydraulic jet units 10 acts to cool the rock. The resultingthermal shock acts in combination with the force of the electrohydraulicjet units to fracture the rock. Metal cutting bits 41 may also be usedafter the rock has been fractured effectuate the complete removal of therock. I

The arrangement of the electrohydraulic jet units 10 and the heatingunits 51 can be reversed on the stand 40 so that the liquid used tofracture the rock by the jet units 10 also permeates the rock, is heatedby the heating units 51 and expands as it turns to steam and subjectsthe rock to both thermal shock and fracturing. Again metal cutting bits41 can be employed to aid in removal of the rock.

FIGS. 5, 6, and 7 of the drawings illustrate one known form of anelectrohydraulic jet unit constructed in accordance with the inventionand suitable for use in the overall systems shown in FIGS. 1. In FIG. 5,a pair of relatively thick, flat, circular steel plates are shown at 31and 32 for supporting insulating sleeves 18 and 19 and the opposedcentral conducting electrodes 16 and 17. The relatively thick plates 31and 32 have an inner, or central flat, circular, cavity defining, thickplate 33 sandwiched between them that also is constructed of steel. Theplates 31, 32 and 33 are held together in assembled relation by means ofa plurality of relatively large, threaded bolts and nuts 34 and 35arranged around the periphery of the plates and inserted through alignedapertures formed in the plates. The two inner faces of the outer plates31 and 32 have suitable O-ring grooves formed therein (best shown inFIG. 7) which coact with coresponding grooves formed in the two faces ofthe inner steel plate 33 and support O-ringe seals 36 and 38 for sealingclosed the space or cavity 39 formed by a central opening in the innersteel plate 33. The ends of the central electrodes 16 and 17 extend intothe central cavity 39.

As best shown in FIG. 6, the central steel plate 33 has a smallpassageway 14 formed therein for supplying liquid to the interior of thecavity 39 as described earlier, and the discharge opening or nozzle 12is formed approximately arcuate degrees from the discharge opening ornozzle 12 as best shown in FIG. 7. FIG. 7 is an exploded view of theassembled structure shown in FIGS. 5 and 6 and illustrates in greaterdetail the construction of each of the outer plates 31 and 32 togetherwith the subtended insulating sleeves 18 and 19 and their centralconducting electrodes 16 and 17 as well as the construction of the inneror central cavity defining plate 33. All of the elements are of heavythick steel plate construction so as to withstand the extremely highpressures built up during operation of the electrohydraulic jet unit asdescribed earlier in the application.

Although the present invention has been described in connection with thepreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention, as those skilled in the art will readilyunderstand. To be particular, while the embodiments of the inventionherein disclosed have been described as adapted primarily for use inmining the vertical surfaces of a laterally extending underground mineshaft 7 or tunnel, the invention is in no way restricted to such use butreadily may be adapted for use in open pit mining and excavation,drilling, descallng, deicing, use as a pneumatic hammer, use in themanner of sand blasting equipment, and other similar applications aswould be obvious to one skilled in the art in the light of the aboveteachings. Accordingly, any such modifications and variations areconsidered to be within the purview and scope of the invention asdefined by the appended claims.

We claim:

1. A process for producing a high energy liquid jet with a confinedchamber provided with an electrical discharge channel and an outletopening which comprises:

' a. supplying a relatively incompressible liquid to said chamber; b.confining the liquid within said chamber;

c. discharging electric energy across the discharge channel through theliquid to'create a shock wave in said liquid; and

d. directing at least a portion of the liquid directionally through theoutlet opening under action of the shock wave whereby the liquid emergesas a high energy liquid jet.

2. The process of claim 1, including the step of applying mechanicalforce to the liquid to increase the energy level of the liquid prior tothe discharge of electrical energy therein.

3. A process for producing a high energy liquid jet with anelectrohydraulic chamber having a shaped outlet nozzle and at least onepair of spaced apart electrodes insulatingly supported within thechamber to define an electric channel, the process comprising: 7

a. confining a relatively incompressible liquid in the electrohydraulicchamber; charging a capacitance to a desired level of electrical energyfrom an electrical power supply;

0. initiating a wave within the electrohydraulic chamber by dischargingthe electrical energy stored. in the capacitance across the electrodesdefining the discharge channel while the electrodes are surrounded bythe liquid in the chamber; and

directing at least a portion of the liquid within the chamber outthrough the outlet nozzle under action of the shock wave as a highenergy liquid jet.

4. The process of claim 3, further including capacitance dividing theelectric energy appearing between the electrohydraulic chamber and theelectrodes defining the electric discharge channel.

5. A process for producing repetitively pulsed high energy liquid jetswith an electrohydraulic chamber having a shaped outlet nozzle and apair of spaced apart electrodes insulatingly supported with the chamberto define an electric discharge channel, the process comprising:

a. providing a continuously available supply of a relativelyincompressible liquid to the electrohydraulic chamber;

b. repetitively charging a capacitance connected to an electrical powersupply to a desired level of electrical energy;

c. repetitively triggering the capacitance to discharge the same acrossthe electrodes while surrounded by the liquid in thechamber to create aseries of shock waves within said chamber; and

d. directing at least a part of the liquid within the chamber outthrough the nozzle under action of each shock wave as a pulsed liquidjet.

6. The process of claim 5, including the step of isolating the liquidsupply from the chamber during electrical discharge.

7. Apparatus for producing a high energy liquid jet comprising:

a. electrohydraulic chamber means having liquid jet I outlet means;

b. electric spark discharge means positioned within said chamber means;

c. supply means connected to said chamber for sup plying liquid to saidchamber;

(1. electric circuit means connected to said electric spark dischargemeans for supplying electric energy to said electric spark means; and

e. switch means in said electric circuit means for selectively supplyingelectric energy to the electric spark discharge means whereby a shockwave is created in the liquid in thechamber means and at least a portionof the liquid is directed out through the outlet means as a high energyliquid jet.

8. Apparatus according to claim 7, wherein said electric circuit meansincludes,

f. capacitance means;

g. high voltage means connected to said electric circuit means forcharging said capacitance means to a desired level of electrical energy;and

h. wherein said switch means in said electric circuit means selectivelydischarges the capacitance means across the electric discharge meanswhereby a shock wave is created in the liquid in the chamber means andat least a portion of the liquid is directed out through the outletmeans as a high energy liquid jet. I

9. Apparatus according to claim 8, wherein the outlet means is shaped toforce the liquid directed therethrough into a relatively cohesive mass.

10. Apparatus according to claim 9, wherein check valve means areincluded for making the electrohydraulic chamber a substantially closedchamber except for the outlet means at the time of electrical discharge.

11. Apparatus according to claim 10, wherein the electric sparkdischarge means comprises a pair of electrodes insulatingly supportedwithin the electrohydraulic-chamber so as to be surrounded by theliquid.

12. Apparatus according to claim 10, wherein each electrode is supportedwithin a conductive shell electrically insulated therefrom andmechanically and electrically connected to the electrohydraulic chamberto form a capacitance voltage divider between the electrodes and theelectrohydraulic chamber means.

13. Apparatus according to claim 12, wherein the chamber means and thecapacitance means are not connected to a common electrical ground andthe electrical discharge means is connected to a common electricalground.

14. Apparatus according to claim 7, wherein the supply means includescheck valve means for preventing reverse flow of the liquid.

directly with said electrohydraulic chamber means, port means fordelivering liquid to the cylinder means and piston means freelyacceleratible within said cylinder means for delivering the liquid fromsaid port means to the chamber means.

1. A process for producing a high energy liquid jet with a confinedchamber provided with an electrical discharge channel and an outletopening which comprises: a. supplying a relatively incompressible liquidto said chamber; b. confining the liquid within said chamber; c.discharging electric energy across the discharge channel through theliquid to create a shock wave in said liquid; and d. directing at leasta portion of the liquid directionally through the outlet opening underaction of the shock wave whereby the liquid emerges as a high energyliquid jet.
 2. The process of claim 1, including the step of applyingmechanical force to the liquid to increase the energy level of theliquid prior to the discharge of electrical energy therein.
 3. A processfor producing a high energy liquid jet with an electrohydraulic chamberhaving a shaped outlet nozzle and at least one pair of spaced apartelectrodes insulatingly supported within the chamber to define anelectric channel, the process comprising: a. confining a relativelyincompressible liquid in the electrohydraulic chamber; b. charging acapacitance to a desired level of electrical energy from an electricalpower supply; c. initiating a wave within the electrohydraulic chamberby discharging the electrical energy stored in the capacitance acrossthe electrodes defining the discharge channel while the electrodes aresurrounded by the liquid in the chamber; and d. directing at least aportion of the liquid within the chamber out through the outlet nozzleunder action of the shock wave as a high energy liquid jet.
 4. Theprocess of claim 3, further including capacitance dividing the electricenergy appearing between the electrohydraulic chamber and the electrodesdefining the electric discharge channel.
 5. A process for producingrepetitively pulsed high energy liquid jets with an electrohydraulicchamber having a shaped outlet nozzle and a pair of spaced apartelectrodes insulatingly supported with the chamber to define an electricdischarge channel, the process comprising: a. providing a continuouslyavailable supply of a relatively incompressible liquid to theelectrohydraulic chamber; b. repetitively charging a capacitanceconnected to an electrical power supply to a desired level of electricalenergy; c. repetitively triggering the capacitance to discharge the sameacross the electrodes while surrounded by the liquid in the chamber tocreate a series of shock waves within said chamber; and d. directing atleasT a part of the liquid within the chamber out through the nozzleunder action of each shock wave as a pulsed liquid jet.
 6. The processof claim 5, including the step of isolating the liquid supply from thechamber during electrical discharge.
 7. Apparatus for producing a highenergy liquid jet comprising: a. electrohydraulic chamber means havingliquid jet outlet means; b. electric spark discharge means positionedwithin said chamber means; c. supply means connected to said chamber forsupplying liquid to said chamber; d. electric circuit means connected tosaid electric spark discharge means for supplying electric energy tosaid electric spark means; and e. switch means in said electric circuitmeans for selectively supplying electric energy to the electric sparkdischarge means whereby a shock wave is created in the liquid in thechamber means and at least a portion of the liquid is directed outthrough the outlet means as a high energy liquid jet.
 8. Apparatusaccording to claim 7, wherein said electric circuit means includes, f.capacitance means; g. high voltage means connected to said electriccircuit means for charging said capacitance means to a desired level ofelectrical energy; and h. Wherein said switch means in said electriccircuit means selectively discharges the capacitance means across theelectric discharge means whereby a shock wave is created in the liquidin the chamber means and at least a portion of the liquid is directedout through the outlet means as a high energy liquid jet.
 9. Apparatusaccording to claim 8, wherein the outlet means is shaped to force theliquid directed therethrough into a relatively cohesive mass. 10.Apparatus according to claim 9, wherein check valve means are includedfor making the electrohydraulic chamber a substantially closed chamberexcept for the outlet means at the time of electrical discharge. 11.Apparatus according to claim 10, wherein the electric spark dischargemeans comprises a pair of electrodes insulatingly supported within theelectrohydraulic chamber so as to be surrounded by the liquid. 12.Apparatus according to claim 10, wherein each electrode is supportedwithin a conductive shell electrically insulated therefrom andmechanically and electrically connected to the electrohydraulic chamberto form a capacitance voltage divider between the electrodes and theelectrohydraulic chamber means.
 13. Apparatus according to claim 12,wherein the chamber means and the capacitance means are not connected toa common electrical ground and the electrical discharge means isconnected to a common electrical ground.
 14. Apparatus according toclaim 7, wherein the supply means includes check valve means forpreventing reverse flow of the liquid.
 15. Apparatus according to claim7, including valve means selectively actuatable to open said jet outletmeans upon electrical discharge of the capacitance means.
 16. Apparatusaccording to claim 7, wherein said supply means includes cylinder meanscommunicating directly with said electrohydraulic chamber means, portmeans for delivering liquid to the cylinder means and piston meansfreely acceleratible within said cylinder means for delivering theliquid from said port means to the chamber means.